not to nit-pick: 1. I only do 1 sql query 2. Gijs Van Tulder uses recursion, while I use while loops. Similar effect. 3. Gijs Van Tulder function only prints out the path as a series of strings. I give it back in an array.
-----Original Message----- From: point of no return [mailto:[EMAIL PROTECTED] Sent: Thursday, October 07, 2004 2:38 AM To: [EMAIL PROTECTED] Subject: Re: [PHP-DB] Recursively determine parent records? http://www.sitepoint.com/print/hierarchical-data-database has a guide on how to do the same thing but in a single SQL query, without looping at all. It is very interesting reading and requires a slight restructuring of how the records are stored to pull off but with the wonderful result in being much faster to retrieve. Chris Gregors wrote: > Here's a piece of some code I wrote that does what you want. You'll need > to change the WhoIsMyParent() function to match your database > abstraction and schema. > > $array = BreadCrumbs($id); > print_r($array); > exit; > > function BreadCrumbs($parent) { > // construct an array of indexes that represents the path back > to the > // root from my current location in the tree. > $PathStack = array(); > array_push($PathStack,$parent); > $MyParent = WhoIsMyParent($parent); > while ($MyParent != 0) { // 0 = top of > the tree > $PathStack[] = $MyParent; > $MyParent = WhoIsMyParent($MyParent); > } > $PathStack = array_reverse($PathStack); > return $PathStack; > } > > function WhoIsMyParent($id) { > $row=FetchRow(QueryDb("select parent from sometable where > id=".$id)); > if ($row == NULL) return 0; > return $row['parent']; > } > > -----Original Message----- > From: Murray @ PlanetThoughtful [mailto:[EMAIL PROTECTED] > Sent: Tuesday, October 05, 2004 11:58 PM > To: [EMAIL PROTECTED] > Subject: [PHP-DB] Recursively determine parent records? > > > > > Hi All, > > > > I have recordset that contains a hierarchical representation of records > where a record's [parentid] field contains the recid of the record > 'above' > the current record. > > > > A representation might look like this: > > > > Recid, parentid, title > > > > 1, 0, Top level record > > 2, 0, Another top level record > > 3, 1, A record under the top level record > > 4, 3, Another level > > 5, 2, A record under the second top level record > > > > If I have currently retrieved the record with recid of 4, I want to work > out > the 'chain' of records that lead back to the top level record it has > been > created under. > > > > In this instance, that chain would look like: > > > > 4, 3, Another level > > 3, 1, A record under the top level record > > 1, 0, Top level record > > > > I'm wondering if anyone can help me work out how to achieve this? > > > > Many thanks in advance! > > > > Much warmth, > > > > Murray > > <http://www.planetthoughtful.org/> http://www.planetthoughtful.org > > Building a thoughtful planet, > > One quirky comment at a time. > > > -- PHP Database Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
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